This invention relates to universal joints, and more specifically to cast or forged universal joint yokes having bearing cup support surfaces which are broached to a finished configuration and location.
It is known to use a broaching operation to bring the bearing cup support surfaces in a cast or forged universal joint yoke to a finished configuration and location. Prior yoke designs which include integral bearing cup positioning and retaining lugs have had material between the lugs and adjacent bearing support surfaces which it is necessary to remove during the broaching operation along with the material that must be removed to bring the support surfaces to a finished configuration and location. The material between the lugs and adjacent support surfaces provide a configuration in conjunction with the support surfaces such that the successive cuts made by the broach must be of non-uniform depth and, in part, substantial depth. This has two undesirable results.
First, this causes chatter of the broach during the broaching operation and thereby dulls the broach more quickly than would be the case if there was no broach chatter. Obviously, broach life is shortened and the speed of production is decreased due to increased down-time for replacing or sharpening the broach. The result is that production costs are higher than would be the case if broach chatter was not present.
Second, this causes the arms of the yoke to be bent slightly during the broaching operation because of the increased force exerted due to the substantial depth over part of the cut. Consequently, the bearing cup support surfaces are finished so that the bearing cups are held with their axes slightly non-coaxial. Such misalignment has the undesirable effect of greatly reducing the life of the bearings held in the yoke.
My improved universal joint yoke overcomes both of the problems described above by providing a design which eliminates the material between the lug and adjacent bearing cup support surfaces so that the broach can make successive cuts which are substantially uniform and are not substantial in depth. As a result, broach chatter and bending of the yoke arms during broaching are eliminated.